The invention relates generally to container packaging, and more particularly to cargo containers which are used to ship products, foodstuffs, and other materials into the United States of America from foreign countries outside the United States. The contents of such containers has become critical in the war against terrorism. It has become extremely important to monitor the contents of such containers for harmful materials, such as explosives, harmful biological material, and radiation materials. The invention is designed to monitor the contents of large or small containers for any harmful materials.
Briefly stated, the invention is in one or more detection devices which are initially placed within a container, depending on the size of the container. The detection devices are designed to send off specific resonant frequency signals which are correlated to any harmful material detected within the container. A hand held or stationary monitor is provided to monitor the container for any signals given off from the detection devices within the container. The detection devices are designed to give off a predetermined amount of background signal. So that if no such signals are received, the container is highly suspect as being tampered with, and such container is quickly removed and its contents examined.